Open head drums are commonly used as storage and transportation containers in many industries. An open head drum typically has an outwardly rolled upper rim, upon which a compressible gasket is placed. A lid, with an annular mating groove dimensioned to fit over the rolled rim of the drum, is placed on top of the gasket. After the gasket is compressed, the lid is held in place by a split closing ring, the ends of which are fastened together with a bolt or lever locking mechanism. In order to maintain the sealing pressure on the gasket, the split closing ring must be dimensioned to fit tightly against the perimeter of the lid and rim.
Present methods of placing the split closing ring include placing it manually in position at the juncture between the lid and drum. Manually placing the closing ring is a relatively slow process, and is accordingly not well-suited for a conveyor processing line operation in which the drums typically arrive at the sealing area at the rate of one drum every 6 seconds. In such operations, it is usually necessary to have more than one worker positioning the split closing ring. Additionally, manual placement of the closing ring entails some risk of injury to the hands of the worker. Further, as the drum is conveyed downstream to the next work station for compression of the sealing gasket and fastening of the closing ring, the closing ring is prone to slipping out of position. Because the combined height of the rolled rim, uncompressed gasket and lid exceeds the cross-sectional height of the split closing ring, the closing ring cannot properly grasp the lid and rim of the drum until the gasket is compressed. Therefore, after manual placement of the split closing ring, the closing ring lies adjacent to the juncture between the lid and the drum, but is not properly seated in position. As the drum travels down the conveyor, the attendant vibrations often cause the closing ring to slip below or above the proper position.
An apparatus for automating split closing ring placement is known in the field. That apparatus, like the apparatus of the present invention, uses magnets to hold a split closing ring in position above an open head drum. Upon activation, the apparatus expands the closing ring and presses the lid downwardly to compress the gasket. A plurality of pins positioned above the split closing ring then push downwardly simultaneously on the closing ring, urging it into position around the lid and drum. A major drawback of the apparatus is that because the expanded split closing ring is pushed down all at once, it has a tendency to overshoot the juncture between the lid and drum. When the closing ring overshoots the proper position, workers must manually reposition the closing ring. A drawback of either of the above methods for placing the split closing ring is that neither provides means for pressing the split closing ring against the juncture for fastening; the only means for tightening the closing ring against the juncture is tightening of the bolt at the ends of the closing ring.